Consensus on digital maps?

Bitstring <[email hidden]>, from the wonderful
person Jim Ford <[email hidden]> said

Quoted message said:

Hi.

I've not been following the various threads on digital maps, but having been
given a section of map printed from Anquet, I was impressed and am
considering going digital.

What's been the consensus on the various maps available (Anquet/Memory Map
etc.)?

I think you're an optimist if you expect consensus on anything (a smart
optimist, since you can at least spell it right).

Most of them have free demos - try before you buy. And do have a look
at tracklogs (www.tracklogs.co.uk) too, especially if you are interested
in 1:25k data for odd bits of the UK off the normal beaten tracks.

--
GSV Three Minds in a Can
Outgoing Msgs are Turing Tested,and indistinguishable from human typing.

GSV Three Minds in a Can <[email hidden]> wrote

Quoted message said:

Bitstring <[email hidden]>, from the wonderful
person Jim Ford <[email hidden]> said

Quoted message said:

Hi.

I've not been following the various threads on digital maps, but having been
given a section of map printed from Anquet, I was impressed and am
considering going digital.

What's been the consensus on the various maps available (Anquet/Memory Map
etc.)?

I think you're an optimist if you expect consensus on anything (a smart
optimist, since you can at least spell it right).

Most of them have free demos - try before you buy. And do have a look
at tracklogs (www.tracklogs.co.uk) too, especially if you are interested
in 1:25k data for odd bits of the UK off the normal beaten tracks.

I went for Tracklogs 1:50k for Derbyshire and Yorks Dales, and it's nice
to plot in all the walks I've done and see a spider's web spreading
throughout the map.

However, I wouldn't buy the 1:50k again, it simply isn't as accurate as
my GPS tracks, and when I tried a couple of walks to a plotted track,
the discrepancies were obvious.

I'd only go for 1:25k in areas of special interest if I buy more.
The 50k is useful for the drive out though, giving an accurate distance
and time, if you set a motoring Naismith of about 35mph. ;-)
--
Gordon

The only digital map I have is the Anquet 1:50,000 version of the Peak
District. It has its uses but when planning one route, an unbelievable
height ascended was shown. This led me to a few experiments to try to
find why such an obvious error had occurred. It was found that if a
route was planned in a riverbed, going DOWN river, a GAIN in height was
reported. Admittedly if the route was reversed, the gain was greater,
but how can you gain height going down river?
Can anyone explain to me why this is so?
Will anyone try it on their digital maps (of any type) to see if rivers
flow up hill to the sea?

--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

censored Gays said:

The only digital map I have is the Anquet 1:50,000 version of the Peak
District. It has its uses but when planning one route, an unbelievable
height ascended was shown. This led me to a few experiments to try to
find why such an obvious error had occurred. It was found that if a
route was planned in a riverbed, going DOWN river, a GAIN in height was
reported. Admittedly if the route was reversed, the gain was greater,
but how can you gain height going down river?
Can anyone explain to me why this is so?
Will anyone try it on their digital maps (of any type) to see if rivers
flow up hill to the sea?

Not being a digital map user, I can only speculate. I would suspect the
Anquet software uses the freely available NASA STRM height data, as a grid
(DEM) model. This stuff is pretty fine scale and measured to the metre
rather than 5 m contours so will include every little undulation and rise
and fall. It probably gives a more accurate answere but treat it with
caution, it was measured from space using radar and uncorrected data has a
number on anomolies, usually drops to 0m where the radar failed to reply
(Cryb Goch and Malham Tarn). These show up in spectacular fashion with
the 3D plug-in for Ozi-Explorer. A Guy somewhere is selling "corrected"
data.

Mandlebrot, the guy who pioneered fractal theory gave the example of the
length of the British coastline. Measure it on a small scale map, then on
a large scale map, then walk it, every time measuring even smaller coves
and bays, until you measure around grains of sand. The length of the
British coastline will increase with every new accuracy in the measurement
until it begains to approach infinity! Now isn`t that a happy thought for
the round the coast walker?...

Ed.

If you want to buy something based on OS 25k (that's what I have) be aware
that they will be changing it all as the new access rights come with the
CROW act. It will then take a little time for the digital people to change
with it.

You're best off holding on for the updated versions, or for a bargain when
the old stuff hits the bucket!

The 2 main contenders here would be Anquet and MM, but look at the demos
before buying owt!

Or get Ozi and scan your own, then when the new maps some out, simply
rescan. Naughty, though!!

Cheers

Lewis

[censored] Gays <[email hidden]> wrote

Quoted message said:

The only digital map I have is the Anquet 1:50,000 version of the Peak
District. It has its uses but when planning one route, an unbelievable
height ascended was shown. This led me to a few experiments to try to
find why such an obvious error had occurred. It was found that if a
route was planned in a riverbed, going DOWN river, a GAIN in height was
reported. Admittedly if the route was reversed, the gain was greater,
but how can you gain height going down river?
Can anyone explain to me why this is so?
Will anyone try it on their digital maps (of any type) to see if rivers
flow up hill to the sea?

Tracklogs TR:

A downstream trip of 7 miles gave 40 metres ascent.

I don't walk down rivers though.....

However -

I did a 10 mile walk many years ago in the Howgills, carrying an ex RAF
altimeter. It was heavy(!) and recorded 2300ft of ascent.

The Tracklogs plot of the same route gave 2365ft of ascent.

Close enough for jazz, I think, bearing in mind the undulations of the
'Owgills, and the fact that I had to keep resetting the altimeter at the
start of each bit of climbing. :-)
--
Gordon

Ed Whittaker said:

censored Gays said:

The only digital map I have is the Anquet 1:50,000 version of the Peak
District. It has its uses but when planning one route, an unbelievable
height ascended was shown. This led me to a few experiments to try to
find why such an obvious error had occurred. It was found that if a
route was planned in a riverbed, going DOWN river, a GAIN in height was
reported. Admittedly if the route was reversed, the gain was greater,
but how can you gain height going down river?
Can anyone explain to me why this is so?
Will anyone try it on their digital maps (of any type) to see if rivers
flow up hill to the sea?

You can get funny effects in Anquet where you are travelling parallel
to the contours. The height data isn't derived from the contours and
the errors can build up.

Quoted message said:

Not being a digital map user, I can only speculate. I would suspect the
Anquet software uses the freely available NASA STRM height data, as a grid
(DEM) model. This stuff is pretty fine scale and measured to the metre
rather than 5 m contours so will include every little undulation and rise
and fall. It probably gives a more accurate answere but treat it with
caution, it was measured from space using radar and uncorrected data has a
number on anomolies, usually drops to 0m where the radar failed to reply
(Cryb Goch and Malham Tarn). These show up in spectacular fashion with
the 3D plug-in for Ozi-Explorer. A Guy somewhere is selling "corrected"
data.

The freely available SRTM data isn't that precise, it is sampled at 3
arc second intervals and is pretty accurate compared to GPS altitude,
though there are voids caused by scattering of the radar by water,
snow or steep slopes. These are quite bad in Scotland where you end up
dirty great big holes in areas like the Cuillin and Torridon. However
these can be fixed with BLACKART.

See http://www.terrainmap.com/rm38.html#srtm_repair
--
Phil Cook looking north over the park to the "Westminster Gasworks"

After much pondering, I ended up going for the Anquet 1:25,000 (Lake
District), because...
-£20 Cheaper than Memory Map for equivalent area.
-MM can only show a tile of mapping at a time in the 3D view whereas
Anquet keeps extending the view seamlessly.
-Would have liked the 3D Aerial photo overlay that comes with MM, but
apparently it is coming soon to Anquet anyway (though at what price?).

Impressions so far...
The 3D view is absolutely brilliant, and helped me identify a hill I'd
seen on a recent walk by its profile (turned out to be Fleetwith
Pike).

I overlayed a couple of tracks I'd recorded from my GPS, and was able
to do a 3D "fly-through" of where I'd been. Though this is good fun,
it doesn't give you a good representation of the walk, because you
can't get right down to ground level (it hovers at 250m above the
ground).

One thing which isn't immediately apparent from the advertising - if
you get the 1:25,000 scale mapping, it doesn't come with the 1:50,000
maps of the same area - they are separate products. It does however
come with a 1:250,000 GB overview.

I haven't played with the other features of the software very much
yet, but am impressed by what I see so far. Feel free to ask specific
any questions about Anquet, and I'll try to get the answers.

Simon
website: The Mountains of England and Wales
http://www.simonedwardes.co.uk

"Simon Edwardes" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

After much pondering, I ended up going for the Anquet 1:25,000 (Lake
District), because...
-£20 Cheaper than Memory Map for equivalent area.
-MM can only show a tile of mapping at a time in the 3D view whereas
Anquet keeps extending the view seamlessly.
-Would have liked the 3D Aerial photo overlay that comes with MM, but
apparently it is coming soon to Anquet anyway (though at what price?).

Impressions so far...
The 3D view is absolutely brilliant, and helped me identify a hill I'd
seen on a recent walk by its profile (turned out to be Fleetwith
Pike).

Most unusual use I've put this to was to track down the loaction of a camp
site in Knoydart. I found a couple of photos on the web of the site and the
surrounding hills. Using the landscape view, I was able to pinpoint the
position pretty accurately.

Quoted message said:

I overlayed a couple of tracks I'd recorded from my GPS, and was able
to do a 3D "fly-through" of where I'd been. Though this is good fun,
it doesn't give you a good representation of the walk, because you
can't get right down to ground level (it hovers at 250m above the
ground).

Use the "F" key to lower the view point and "R" to go back up (I remember
them as Rise and Fall)

Quoted message said:

One thing which isn't immediately apparent from the advertising - if
you get the 1:25,000 scale mapping, it doesn't come with the 1:50,000
maps of the same area - they are separate products. It does however
come with a 1:250,000 GB overview.

The good thing about this is that you can build up a number of "layers" of
map data. For instance, I've got all of the 1:25k Harveys mapsof Scotland in
Anquet. When I'm in area where Harveys data is available, it's selectable
from the drop-down menu.

Quoted message said:

I haven't played with the other features of the software very much
yet, but am impressed by what I see so far. Feel free to ask specific
any questions about Anquet, and I'll try to get the answers.

Ditto. I've been using Anquet for over a year now - In fact having it
persuaded me to buy a GPS too (grrr).

druidh

I said:

Quoted message said:

...3D fly-through/view ... doesn't give you a good representation of the
walk, because you can't get right down to ground level (it hovers at 250m
above the ground).

Druidh said:

Use the "F" key to lower the view point and "R" to go back up (I remember
them as Rise and Fall)

I've used the "F" key, but still can't get lower than 250m above
ground level. Is there a setting I'm missing somewhere ?

Cheers, Simon
website: The Mountains of England and Wales
http://www.simonedwardes.co.uk

Simon Edwardes <[email hidden]> wrote

Quoted message said:

I said:

Quoted message said:

...3D fly-through/view ... doesn't give you a good representation of the
walk, because you can't get right down to ground level (it hovers at 250m
above the ground).

Druidh said:

Use the "F" key to lower the view point and "R" to go back up (I remember
them as Rise and Fall)

I've used the "F" key, but still can't get lower than 250m above
ground level. Is there a setting I'm missing somewhere ?

The eject button should bring you floating down to ground level after a
brief spell of positive vertical acceleration.
--
Gordon

"Simon Edwardes" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

I said:

Quoted message said:

...3D fly-through/view ... doesn't give you a good representation of

the

Quoted message said:

Quoted message said:

Quoted message said:

walk, because you can't get right down to ground level (it hovers at

250m

Quoted message said:

Quoted message said:

Quoted message said:

above the ground).

Druidh said:

Use the "F" key to lower the view point and "R" to go back up (I

remember

Quoted message said:

Quoted message said:

them as Rise and Fall)

I've used the "F" key, but still can't get lower than 250m above
ground level. Is there a setting I'm missing somewhere ?

I was using 1:50,000 data and if I go "out to sea" and pop up the display
box (Tools. . . .Virtual Landscape Settings. . . .Display . . . All), I see
my "altitude" as 50M.

After a bit of digging, I found a Terrain.ini file in the Anquet Maps\System
Folder. It shows the minimum Hover Height as 50M for 1:50,000 and 250M for
1:250,000. I've now edited the 1:50,000 value to 5M and it seems to work
fine. Any lower causes some strange "ground effects".

Now then - I wonder what all those other settings are for. . . . .

druidh

Gordon <[email hidden]> wrote in
news:[email hidden]:

Quoted message said:

GSV Three Minds in a Can <[email hidden]> wrote

Quoted message said:

Bitstring <[email hidden]>, from the wonderful
person Jim Ford <[email hidden]> said

Quoted message said:

Hi.

I went for Tracklogs 1:50k for Derbyshire and Yorks Dales, and it's
nice to plot in all the walks I've done and see a spider's web
spreading throughout the map.

However, I wouldn't buy the 1:50k again, it simply isn't as accurate
as my GPS tracks, and when I tried a couple of walks to a plotted
track, the discrepancies were obvious.

I'd only go for 1:25k in areas of special interest if I buy more.
The 50k is useful for the drive out though, giving an accurate
distance and time, if you set a motoring Naismith of about 35mph.
;-)

My experience has been somewhat different, I have Tracklogs 1:50k and find
it suits my needs (which may be different to yours of course). I walk
mainly in Dorset which has pretty good paths, although I have also walked
in the Lake District and the Black Mountains. At first I thought I would
need 1:25k mapping as that is what I had always used in paper maps, but now
I find the only thing I am missing is field boundaries and as the GPS tells
me exactly where I am, these are less important.

Generally I print the 1:50k map (with intended track) twice full size and
laminate it. Sometimes I might scan the 1:25k paper map and laminate both
sheets together.

Bitstring <[email hidden]>, from the
wonderful person John Yale <[email hidden]> said

Quoted message said:

Gordon <[email hidden]> wrote in
news:[email hidden]:

Quoted message said:

GSV Three Minds in a Can <[email hidden]> wrote

Quoted message said:

Bitstring <[email hidden]>, from the wonderful
person Jim Ford <[email hidden]> said
>Hi.
>

I went for Tracklogs 1:50k for Derbyshire and Yorks Dales, and it's
nice to plot in all the walks I've done and see a spider's web
spreading throughout the map.

However, I wouldn't buy the 1:50k again, it simply isn't as accurate
as my GPS tracks, and when I tried a couple of walks to a plotted
track, the discrepancies were obvious.

I'd only go for 1:25k in areas of special interest if I buy more.
The 50k is useful for the drive out though, giving an accurate
distance and time, if you set a motoring Naismith of about 35mph.
;-)

My experience has been somewhat different, I have Tracklogs 1:50k and find
it suits my needs (which may be different to yours of course). I walk
mainly in Dorset which has pretty good paths, although I have also walked
in the Lake District and the Black Mountains. At first I thought I would
need 1:25k mapping as that is what I had always used in paper maps, but now
I find the only thing I am missing is field boundaries and as the GPS tells
me exactly where I am, these are less important.

That's what I use 1:25k for, walking around (semi)-civilized Shropshire
... I can see which side of the hedge the footpath is =supposed= to be on
(although 50% of the hedges and field boundaries have been ripped out
since the maps were surveyed .. one or two new boundaries added, but
only pig wire, not hedges). Being within 2-3 metres of the footpath, but
on the wrong side of the hedge/fence/ditch/stream, can make for a much
more unpleasant walking experience (and sometimes a significant
backtrack).

Quoted message said:

Generally I print the 1:50k map (with intended track) twice full size and
laminate it. Sometimes I might scan the 1:25k paper map and laminate both
sheets together.

I print the 1:25k maps at 1:12500, usually double sided, stick them in
A4 transparent pockets, seal the open edge with 'magic tape', and off
you go - waterproof, nearly indestructible (as regards folding, stuffing
in pockets etc.) and large enough to read even when you have rain all
over your glasses.

--
GSV Three Minds in a Can
Outgoing Msgs are Turing Tested,and indistinguishable from human typing.

John Yale <[email hidden]> wrote

Quoted message said:

Gordon <[email hidden]> wrote

Quoted message said:

I'd only go for 1:25k in areas of special interest if I buy more.
The 50k is useful for the drive out though, giving an accurate
distance and time, if you set a motoring Naismith of about 35mph.
;-)

My experience has been somewhat different, I have Tracklogs 1:50k and find
it suits my needs (which may be different to yours of course). I walk
mainly in Dorset which has pretty good paths, although I have also walked
in the Lake District and the Black Mountains. At first I thought I would
need 1:25k mapping as that is what I had always used in paper maps, but now
I find the only thing I am missing is field boundaries and as the GPS tells
me exactly where I am, these are less important.

Generally I print the 1:50k map (with intended track) twice full size and
laminate it. Sometimes I might scan the 1:25k paper map and laminate both
sheets together.

Fair enough. I just like, and enjoy(!) the detail on the 1:25,000, and
they are more accurate, simply because of the scale and the degree of
'cramming' to get everything in on 1:50,000 (or nearly everything).
--
Gordon

Simon Edwardes said:

I've used the "F" key, but still can't get lower than 250m above
ground level. Is there a setting I'm missing somewhere ?

You probably don't want to go much lower than 50m anyway. In Trailgauge
you can go right down to 0m but at this altitude your immediate view
consists mostly the spot where you are on the map magnified enormously
which means you can't read any detail on it.

--
Andrew Whaley, author of :-

Trailgauge - Shareware 3D GPS Mapping Software
Free Download from http://www.trailgauge.com

Andrew Whaley said:

You probably don't want to go much lower than 50m anyway. In Trailgauge
you can go right down to 0m but at this altitude your immediate view
consists mostly the spot where you are on the map magnified enormously
which means you can't read any detail on it.

It's not the immediate view I'm interested in. What I want is an idea
of what I'll be able to see in the distance, for example the panorama
from a summit. It's a bit of a fiddle (and sometimes impossible)
moving your viewpoint in the software until your viewing altitude is
level with the summit.

Simon
website: The Mountains of England and Wales
http/www.simonedwardes.co.uk

Simon Edwardes <[email hidden]> wrote

Quoted message said:

Andrew Whaley said:

You probably don't want to go much lower than 50m anyway. In Trailgauge
you can go right down to 0m but at this altitude your immediate view
consists mostly the spot where you are on the map magnified enormously
which means you can't read any detail on it.

It's not the immediate view I'm interested in. What I want is an idea
of what I'll be able to see in the distance, for example the panorama
from a summit. It's a bit of a fiddle (and sometimes impossible)
moving your viewpoint in the software until your viewing altitude is
level with the summit.

I often 'walk' to the top of a hill or mountain in Tracklogs and take a
leisurely look around, no problem. In fact, I've done a few tops in
better time than I ever did in RL. :-)
--
Gordon

Ed Whittaker said:

censored Gays said:

It was found that if a route was planned in a riverbed, going DOWN
river, a GAIN in height was reported. Admittedly if the route was
reversed, the gain was greater, but how can you gain height going
down river?

Not being a digital map user, I can only speculate. I would suspect
the Anquet software uses the freely available NASA STRM height data,
as a grid (DEM) model. This stuff is pretty fine scale and measured
to the metre rather than 5 m contours so will include every little
undulation and rise and fall.

Wrong unfortunately. The height grid is very low res, only 1 point
every 50m. The way Anquet uses the data is to average the height of
each point (or pixel, I'm not sure) with the surrounding points in order
to smooth out the sharp transistions.

Quoted message said:

It probably gives a more accurate answer

Unfortunately not. If you plot a route that goes straight up or
downhill, i.e. crossing the contour lines at a perpendicular angle, you
tend to get a very accurate result. It's when you trace a route
parallel to the contours, or along rivers, or cliff edges, that you get
the most inaccurate results. The worst errors occur when you trace a
line diagonally, particularly next to steep drops, since the line may
cross alternating high and low altitude points, resulting in a jagged
track and loads of ascent, even though you may be walking along a flat
path along a cliff edge.

A good example is the Graig Fan Ddu ridge in the Beacons. Looking at
the profile it looks more reminiscent of a walk along the northern
Rhinogs rather than the smooth ridge walking of the Beacons.

The best way to tell if you can trust the ascent or not is to study the
route profile. If it looks jagged where it should be smooth then you
can't. You can edit the route points a bit to give a slightly better
profile, but you can't fix it completely.

Paul
--
http://www.wilderness-wales.co.uk
http://www.wildwales.fsnet.co.uk